The average opening temperature is stamped on the thermostat. The number 88 indicates that the thermostat is used in Central European countries. The thermostat for Northern Europe has a higher opening temperature. The thermostat can be tested by mounting it and hanging it by a piece of wire in a tank filled with cold water.
In this case, you need to ensure that the thermostat does not touch the bottom or walls of the tank. Hang the thermometer in a similar manner (see figure 127). Heat the water gradually and monitor at what temperature the thermostat begins to open. This should happen at around 88°C. At 100°C, the thermostat should open fully. The thermostat valve should rise. This measurement is extremely important because it affects the frictionless circulation of the coolant.
Figure 127. Checking the thermostat.
When installing the thermostat, both sides of the new seal must be lubricated with sealant.
The stem in the thermostat should be at the top and fit into the groove on the inside of the fitting.
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Adjust the coolant level and check the system for leaks.